One more than however many I personally know, of course :).
I suppose the only defensible definition of the term would be more than one language, with some qualifier like "for any given context", because using C++ to serve your JavaScript app isn't polyglot. But then we just argue about how big a context is - are API servers and systems of record the same context?
A more fruitful perspective might be to look at how the decision to adopt a new language etc is made. If an individual developer can do it, it's a potentially polyglot environment, whether that potential has been realised or not. If it requires an organisation-wide process (whether CTO decree or consensus at an all-hands meeting), it's unlikely to be a polyglot environment.
This perspective is definitely a product of my own particular experiences, though, and might not be generally relevant.
I suppose the only defensible definition of the term would be more than one language, with some qualifier like "for any given context", because using C++ to serve your JavaScript app isn't polyglot. But then we just argue about how big a context is - are API servers and systems of record the same context?
A more fruitful perspective might be to look at how the decision to adopt a new language etc is made. If an individual developer can do it, it's a potentially polyglot environment, whether that potential has been realised or not. If it requires an organisation-wide process (whether CTO decree or consensus at an all-hands meeting), it's unlikely to be a polyglot environment.
This perspective is definitely a product of my own particular experiences, though, and might not be generally relevant.